Out of San Francisco? Ok, but exactly how do they plan to force them out?
The California DOJ has a complete list of pistol buyers from around 1989 to the present. They can simply cross reference this list and go collect the guns of those who bought since 1989. That a$$wipe AG, Bill Lockyer, has been using this list to track down those who have come under a domestic violence restraining order in order to confiscate their firearms.
Ask them for a date?